One dimension (1D) MgCo2O4 was successfully prepared by a facile one-step route and their structural, optical and electrochemical properties have been investigated. The field emission scanning electron microscopy and transmission electron microscopy images illustrates rod like nanostructures with length ranges around 120 nm. The optical band gap of MgCo2O4 was estimated around 4 eV. Then the synthesized product was utilized for electrochemical performance to modify the glassy carbon electrode. Electrochemical tests exhibit high specific capacitance ~752 F g−1 at 2 mA cm−1. The enhanced electrochemical performance is mainly due to the rod like nanostructures, which allows rapid transportation of electrolyte ions which is in favor of developing rate capability of the electrodes. It was believed that, the 1D MgCo2O4 nanostructures may be promising potential product for energy storage device application in supercapacitor.

Biosynthesis of metallic silver nanoparticles has now become an alternative to physical and chemical approaches. In the present study, silver nanoparticles (AgNPs) were synthesized from Cavendish banana peel extract (CBPE) and characterized by UV–visible spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, Atomic force microscopy (AFM), Field emission scanning electronic microscope (FESEM), Dynamic light scattering (DLS) and zeta potential (ZP). The AgNPs formation was confirmed by UV–visible spectroscopy through color conversion due to surface plasma resonance band at 430 nm. The effect of pH on nanoparticle synthesis was determined by adjusting the various pH of the reaction mixtures. The crystalline nature of nanoparticles was confirmed from the XRD pattern, and the grain size was found to be around 34 nm. To identify the compounds responsible for the bioreduction of Ag+ ion and the stabilization of AgNPs produced, the functional group present in Cavendish banana peel extract was investigated using FTIR. AFM has proved to be very helpful in determining morphological features and the diameter of AgNPs in the range of 23–30 nm was confirmed by FESEM. DLS studies revealed that the average size of AgNPs was found to be around 297 nm. Zeta potential value for AgNPs obtained was −11 mV indicating the moderate stability of synthesized nanoparticles. The antibacterial activity of the nanoparticles was studied against Gram-positive and Gram-negative bacteria. Biosynthesized AgNPs showed a strong DPPH radical and ABTS scavengers compared to the aqueous peel extract of Cavendish banana.

•CTAB is excellent capping agent for ZnO nanoparticles.•Band-gap energy was calculated using UV–Visible spectra.•The chemical bonding with ZnO is confirmed by FT-IR spectra.•AFM films exhibited very smooth surface and good crystal structures.•Optoelectronic device like tunable light emitting diode in near future.The presence of surfactant (CTAB) at three different concentrations viz., (0.5, 1 and 1.5 M) on zinc oxide (ZnO) nanocrystalline at 550 °C was synthesized. The optical properties of each surfactant capped zinc oxide nanocrystalline were investigated using UV–Visible absorption. The characterization of these nanocrystalline was performed by X-ray diffractometer Spectrum (XRD), Scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), and Atomic force microscopy (AFM) and Fourier transformer infrared (FTIR) spectroscopy. The effect of CTAB on the morphology of the ZnO was studied by SEM/EDS which revealed that the diameter of the product is in the range of 42–70 nm. Out of the three surfactant concentrations CTAB (0.5 M) capped zinc oxide nanoparticle has smallest crystalline size of 19.4 nm. Thus, the presence of surfactant on the surface of zinc oxide plays a significant role in reducing defect. The excitonic UV emission has been observed at 275 nm.Graphical abstract

•The present work confirms the optical absorption and band gap of ZnO nanoparticles.•The functional groups and the chemical bonding with Fe are confirmed by FTIR spectra.•AFM has proved to be very helpful in the various morphological features and parameters.•Optoelectronic device like tunable light emitting diode in near future.An investigation on Fe-doped ZnO (Zn1−xFexO, x = 0, 0.03, 0.06 and 0.09 mM) nanopowder have been synthesized by co-precipitated method annealed at 550 °C were reported. The structural, morphological and optical properties of the samples were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectra (EDS) analysis, Atomic Force Microscopy (AFM), UV–Visible spectroscopy, and photoluminescence (PL) techniques, Fourier transform infrared (FTIR) spectroscopy. The XRD spectrum shows all the samples are hexagonal wurtzite structure. The presence of functional groups and chemical bonding are confirmed by FT-IR. The PL spectra of the Zn1−xFexxO systems show that the shift in near band edge (NBE) UV emission from 344.54 to 364.21 nm and a shift in green band (GB) emission from 484 to 540 nm which conforms the substitution of Fe into the ZnO lattice. UV–Visible measurement showed a decrease in the energy gap with increasing Fe content, probably due to an increase in the lattice parameters. It is also found that these results are in good agreement with other calculated and experimental results.Graphical abstractPhotoluminescence (PL).